Ladder



Oct. 17, 1961 H. G. ARNOLD 3,004,625

LADDER Filed Sept. 1, 1959 2 Sheets-Sheet 2 3 INVENTOR. I FIG] HAROLD G. ARNOLD ATTYS.

United States Patenfb This invention relates to ladders, and is more particularly concerned with metal or similar ladders and with the construction of and manner of securing rungs to the "side rails thereof.

It is the general object of the invention to provide an 7 improved, relatively lightweight but strongand' durable ladder made from channel shaped side rails 'and substantially tubular rungs. a 'Another object of the invention is to provide a ladder of the character described made from aluminum alloy extrusions.- Another object of the invention is the provision of a tubular rung for a ladder, the rung having at least one flat side which is inclined to the plane of the side rails of the ladder so that the flat side of the rung will be substantially horizontal whenthe side rails are inclined to normal ladder climbing position. a t

Another object of the invention is the provision of a ladder formed from tubular rungs and channel-like side rails and wherein improved means are provided for securing the ends of the rungs to the side rails in a particularly strong and load-bearing relation therewith.

3,004,625 7 Patented Oct, 17, 1961 i; 2 positioning of a flat surface of the 'rung when the side rails of the ladder are inclined to normal ladder use position; 7 i v i FIG. 5 is a view, similarto FIG. 4, of a modification of the ladder of the invention;

FIG. 6 is a'perspective view of the pad shown in FIG. 5; and a d v h FIG. 7 is a view, similar'to FIG. 4,.of'a further modification of the invention.

Referring to the drawings, the numeral 10 indicates generally. a pair. .of siderails of a lower section 12 of an extension type ladder having an upper section 14 slidably mounted upon the lower section 12, the upper section 14 havingside rails 16. The side rails 10 are joined with rungs 18, and the side rails 16 by rungs 20.

' Looking now at FIG. 2 fora-better understanding of the details of the invention, each side rail 10 is'made of channel shape as illustrated including a base portion 22 and side flanges 24. e The outside of the base 22 is generally made harm the manner shown whereas the inside of the base 26 is preferably crowned, to be thickest at its Another object of the invention is the provision of a jects which will become apparent as the description proceeds, are achieved by theprovision of the combination in a ladder of side rails of a channel shape in cross section, a plurality of rungs each having a hollow tubular shapein cross section with at least one flat side, a pad assisting in securing each rung end we side rail, each pad being a short section of channel shape secured to and fitting between the side flanges of each channel-shaped side rail in oppositely facing positions so that the bases of the channel sections of each side rail and pad are spaced apart, each rung end extending through aligned mating holes in the side rail "and pad, 'means on each rung to abut against one side of the combined pad and side rail, the extreme end of each rung being pressed over against the other side of the combined pad and side rail, each rung beingpositioned with its flat side uppermost andhorizontal to provide a step surface when the side rails are in a normal inclined position of use. .A plug may be provided to close the end of each rung, and each pad may have one of its side flanges oflset from the adjacent side flange of the side rail to allow sliding fit with a similarly formed portion of another ladder section.

For a better understanding of the invention reference should be had to the accompanying drawings wherein FIG. 1 is a front elevation, partly broken away, of a two-section, extension-type ladder incorporating the principles of the invention;

FIG. 2 is a cross sectional view, taken substantially on line 22 of FIG. 1 and better illustrating the manner of securing the rungs to the side rails;

FIG. 3 is a cross sectional view taken substantially on line 3-3 of FIG. 1, again illustrating the manner of securing a rung end to the side rail, and also illustrating the sliding interfit between the ladder sections;

FIG. 4 is a sectional view taken substantially on line 4-4 of FIG. 1 and better illustrating the cross sectional shape of a rung and specifically showing the horizontal center to thereby increase the strength and load bearing characteristics of the side rail.

. Each side rail 10 is preferably made; in the form of an aluminum or an aluminum alloy extrusion. However, the

side rails 10 can be made from combinations of fiberglass and resin, and it is likewise possible to utilize combinations of an aluminum alloy extrusion with a fiberglass and resin cover therefor. I I

Cooperating witheach side rail 10 are a plurality of pads 28 each formed of a relatively short, substantially square section of channel shapehaving a flat base portion 30, the inside ofithe basebeing preferably crowned as at 32 for increased strength, and having side flanges 34. Each pad 28 has its flanges 34 of a dimension to fit between the fianges 24 .of .the side-rail 10, but with the bases of the oppositely facing; channel sections being spaced apart a distance-W to give a particularly. excellent, spaced, double bearing load distribution between the rung 18 and the side rail 10. Each pad 28 is suitably secured in the position shown in FIG. 2, and this canbe-accomplished by brazing or welding the pad 28 in position, usually between the flanges 24and34. A 1 j, The pad 28 and side rail 10 are provided with aligned holes therethrough for the reception of the end offthe rung 18, the holes being complementary to or in mating relation with the cross sectional contour of the rung 18 in a manner that will be understood. If the rung 18 is formed with a triangular cross section, as best ,seen in FIG. 4, the holes inthe pad 28 and side rail 10 will be similarly shaped and will slidably receive the end of the n 1" 3 1.

I Each rung 18 is formed with suitable means, such as a rib 40 spaced from the end of the rung which rib engages with the flat base of the pad 28, and the extreme end of each rung 18 is pressed, rolled, or otherwise deformed over against the flat base 22 of the side rail 10 to draw the nb 40 tightly against the pad 28 and to very eflectively secure the end of the rung 18 to the side rail and pad. If desired, although not normally necessary, the rung can be brazed or welded in position. A plug 44 is generally employed to close the end of the rung, this plug 44 being suit-ably pressed, rolled, brazed, or welded in position around the roller over end 42 of the rung 18.

Before leaving the showing of FIG. 2 will be recognized that one of the flanges 34 is offset from the flange 24 along one edge of the side rail 10, if the ladder is to be made as a section of an extension ladder, so as to be able to receive the other similarly formed but oppositely turned section of the extension portion of the ladder,

y and indicated at 46 in chain dotted lines. If the ladder Suifice it to say with respect to FIG. E3 "thateach side 1 rail channel is .turned in theopposite direction so that the open channel side faces outwardly rather than :inwardly. This :figure also illustrates in solid lines the manner of slidably interlocking the sections 512 and 16 of the completeladder. l a 1 Having reference now to FIG. :4 :ofthe:drawings,:-this specifically shows-that each rung 18 isimade -as n-arhollow tube, with at vleast one side of the tube being Hat, -.and with this flat :side, indicated by the nuineralfi50 being positioned uppwermos-t-anfd substantiallyihorizonta-l when theside rail -"is'positioned-at an incline to the' vertical in whatmight be called normal ladder climbing position. This means that a flat horizontal lupper-surfaceis ;provided on-each rung 18 providing astep surface. This relatively flat surface '50 may be --formed corrugated in the manner illustratedin FIG. 4 if desired.

Each rung 18 is-preferably madeof hollow triangular shape as illustrated which gives great strength of inver-te'd arch formto the rung, and-each rung is preferably made as an aluminum alloy extrusioninthe form illustrated, the 'ribs or other-shoulderneans-40 being'upset into-the-rungprior to assembly with the side rail' 10 and the pad 28. V A modified pad or reinforcing member '28a-isshown secured-to a side rail 10a in FIG. 5. The pad 28ais of triangular shape and has an open center 60 contoured complementaryto vthe periphery of a ladder; rung 18a. The pad 28a rnay be made from anysuitable material, such as plastic, fiberglass and .resin, metal, or 1 woodand it may cemented, welded or brazed or otherwise secured to tlie side-rail 10a for reinforcingthereof. I A further pad 286- in the'shape of =a'V or U" is suitably secured to'theladder side rail ;10b in FIG. 7 immediately below'a ladder rungopening-62 formedin the side rail. The pad 28b is made from any material asgsuggested for manufacture of the pad'28a. 'Both' pa'ds 28a "and 28b are, of course, provided for reinforcing the ladder-side rail at the ladder rung.

Whilein accord with the patent statutescertain-best known embodiments of the invention have been "illustrated and describedindetail, it is 'to be specifically-understood "that the invention is not to be imited thereto or thereby, but that its scope is defined in the appended claims. 7 j e What is'claimedis: r

1. The combination inaladder of a-pair of channelshaped side rails,'rungs joining=the side rails, a plurality of channel-shapedpad means,- each padmeans assisting in joining a rung end to the side rail, each pad means .havingtheflanges of its channel fitting between theflanges of the channel of the side rail but oppositely facing so that the bases of the channels of each side rail and pad apertured to receive the end of the rung engage with spaced portions of the :rung, .the pad means having at least oneof the side flanges ofiset from the adjacent side flange oftheside :rail to-lallow; sliding fit with a similarly formed portion of another ladder section andvalso having the end=of saidoffset side flange ofzeach pad formed with an additional -flange to engage with the base of the side rail channel and the adjacent side flange of the side rail, channel, :and means for holding the side ,rail and padtogether and the rung afiixed;thereto.

l .2. The combination in a ladder of side .rails leach formed of an aluminum alloy extrusion andeach having achannehshapein .crosssection, :the outside of ,the

base :of ,the vchannel being flat and the inside being 7 crowned :to be :thickest at the center, vva :plurality; of thugs each formed of an aluminum alloy extrusion having @a hollow triangular shape 'iinzcross section with oneeside Ofthe tflanglebeing longitudinally corrugated, a pad assisting in securing each rung end to the side rail, each pad being a short section of an aluminum alloy extrusion of channel shape secured and fitting between the side flanges of each channel shaped side rail .in oppositely acingposition so that the-bases ofthe channel sections of each side rail and pad-are spaced apart, .the outside of the base of the channel of the padlbeingflat and the inside of thebase .being crowned to be thickest at the center, each rungend extending throughaligned triangulare holes "in thelsiderail a nd pad, a vrib around each rungto abutagainst'one side ofthe combined pad and side rail, the endofeach rung being-pressed over against thelother-side of the combined pad and side rail, aplug closingithe' end'ofeach rung, each song being positioned with its corrugated surface uppermost and horizontal to provide a step surface when the side rails are in a nor- 'mal inclined position against alwall, eachpadzhaving one of its side flanges ofiset from the adjacent side flange ofthe side railto allow sliding fit with a similarly'formed portion-of another ladder section, but with the end of the offset side flange of each -pad beingformedto engage with'the base-of the-side rail and theadjacent side flange of the side rail.

lReferencesiCitedin the fileof'this patent "UNITED'STATES PATENTS 

